The following information is provided to assist the reader in understanding technologies disclosed below and the environment in which such technologies may typically be used. The terms used herein are not intended to be limited to any particular narrow interpretation unless clearly stated otherwise in this document. References set forth herein may facilitate understanding of the technologies or the background thereof. The disclosure of all references cited herein are incorporated by reference.
The invention concerns methods and devices for detection of the concentration of at least one gaseous target substance in a gas, as well as the use of a gas monitoring or gas measurement device.
Detectors for gaseous target substances such as ammonia are basically familiar (CH 686981 A5, DE 3841622 A1). Electrochemical ammonia gas sensors are based, e.g., on the principle of direct oxidation of ammonia or measurement of the change in the pH value.
It has been observed that the performance of ammonia gas sensors slackens off upon long-term exposure, even at slight concentrations. For constant gas concentration, the measurement values of ammonia gas sensors tend toward zero over the course of time. This means that an ammonia-free environment is indicated, even though ammonia is present in the environment.
Therefore, the problem is to develop methods and devices which allow for the detection of a stable measurement of the gas concentration such as ammonia concentration in the surroundings over time.